Interlocking door seam

ABSTRACT

An interlocking door seam provides a stronger seam for double doors, making them less subject to attack by prybars and the like. Particularly for central mail stations (CMS) and central box units CBU, double doors present there are subject to attack by prybars and the like that force the locks and allow thieves to rifle the contents of the enclosed mail boxes. Attachment of interlocking door seam of the present invention to the first edge of the first double doors protects that first edge from prybar attacks. The adjoining edge of the second double door then releasably fits into a convex strip that protects the adjoining edge of the second double door, thereby protecting it from prybar attack. The interlocking door seam allows normal operation of the double doors while decreasing the risk to the central mail station of prybar attack at the seam between the double doors. Flanges present along the free edge of the convex strip provide easy engagement of that free edge. Gaps between such flanges accommodate shelving inside the central mail station. Construction of the interlocking door seam of the present invention by tempered steel or hard and durable materials provides enhanced protection from prybar attack.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This patent application is related to U.S. patent applicationSer. No. 09/273,682 filed Mar. 22, 1999 for INTERLOCKING DOOR SEAM,which application is incorporated herein by this reference thereto.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to door protection and the like and moreparticularly to a pry-proof seam for interlocking mail station doors.

[0004] 2. Description of the Related Art

[0005] In the past, mail boxes for the delivery and receipt of mail havebeen associated with individual dwellings such as single familyresidences. The mailperson on foot could deliver mail to the mail box,or by driving a mail truck or the like, deliver the mail to mail boxessituated adjacent to the road.

[0006] Recently, tampering with mail left in such mail boxes has becomea problem such that the mail must be secured under lock and key. Thisalso provides some privacy for the recipient of the mail. Additionally,central box units or central receiving stations are often installed innew home developments. These central units contain a plurality ofindividual mail boxes for several of the residents in the adjacent area.The mailperson then only has to stop at the central station to delivermail to a number of people simultaneously, allowing him or her to covera larger number of residents with mail delivery.

[0007] The central box units used in such new housing developments oftenhave a five sided box unit with the sixth side accessible via lockabledouble doors. These double doors often have a central seam as they arehinged on their outward sides. By unlocking the double doors, they swingoutward to open up the central postbox area for simultaneous delivery bythe mailperson. The side opposite of the double doors may have a numberof individually locked mail boxes so that each individual with a mailbox may retrieve their mail separately and securely as each key isunique to the appropriate mail box.

[0008] Postal regulations control the construction of such central boxunits in order to provide durable and accessible mail stations to whichthe mailperson can deliver mail. However, such postal regulations maypresume that the mail stations are subject only to environmental attack,such as by wind or rain. Unfortunately, it is not difficult to take aprybar, such as a crowbar or the like, and force it in between the seampresent between the two double doors. The doors are then jimmied bypopping the lock bar out from its place behind the second door. Upon soforcing the double doors open, the mail is available to any thief suchas the one who originally used the prybar. Checks and other financialinstruments may be stolen and fraudulently converted into cash,providing the incentive to break and enter into other central post boxstations or even the same one on an intermittent or regular basis.

[0009] Consequently, there is a need in the art to provide means bywhich the seam between the two double doors in central post box stationsmay be less subject to attack by prybars and the like. The presentinvention provides a solution to this criminal problem while maintainingthe easy and desirable access necessary for the central post boxstation.

SUMMARY OF THE INVENTION

[0010] The present invention provides means by which the central seambetween two double doors of the central post box station may beprotected from prybars and the like. This prevents thieves from jimmyingthe lock or otherwise forcing the doors open with prybars so that thecontents of the mail station can be rifled in order to steal valuablemail contained therein.

[0011] The interlocking door seam of the present invention has a firststrip generally extending straight along its length. An extending flangealong this first concave strip allows it to securely attach to a firstone of the double doors in the central post box station. The edge of thefirst double door is confined and protected by the interstitial spacedefined by the concave nature of the first strip. The first strip bendsaround the edge of the first door holding it therein even though theedge of the door may be angled at its end thus occupying slightly morespace than a straight door would.

[0012] While the first concave strip is attached to the first doubledoor, the free end of the first concave strip bends around, backing awayfrom the concave interstitial space of the first concave strip. In thebending away from the first concave strip, a second convex strip isdefined that can receive the second double door at its free end. Theinterstitial space defined by the second convex strip allows the releaseor engagement of the free end opposite the hinges of the second door.When the second double door edge fits into the second convex strip, itis protected and shielded from the active end of a prybar or the like.In an additional embodiment, flanges may be present that aid and guidethe entry of the second double door edge into the convex strip. Suchflanges may define gaps between them in order to accommodate shelvingdefining individual post boxes within the central mail station.

[0013] By providing an interlocking door seam for central post boxstations, the central stations are rendered more secure from forcedentry, thereby creating more privacy and less risk of holding mail inthe central mail station. Additionally, the interlocking door seam ofthe present invention is easily accommodated by existing central postbox stations, or central base units, with their post boxes in a retrofitprocedure.

[0014] The interlocking door seam may be incorporated en masse into acluster box unit (CBU) in order to provide a more secure mail deliverysystem. Additional security measures may also be taken beyond that ofprotecting the common seam between the two double doors in such a CBU.With respect to the double doors, a central sliding linkage may be usedthat slidably engages door pins present on the facing sides of thedouble doors so that they are held closed until the sliding linkage islifted from place. Held downward by its own weight under gravity, thesliding linkage prevents the door pins from disengaging the slidinglinkage. However, upon the post person opening the mail retrieval doorand lifting the sliding linkage lever, the entire sliding linkagedisengages the door pins so that both doors are able to swing free andexpose all of the interior mail slots.

[0015] Additional security is provided by the individual mailbox slotdoors. Instead of having a cam simply protrude through the mailbox slotdoor frame, an extending side flange to the mailbox slot door is alsopresent and is a physical structure through which the cam passes inorder to securely and fully lock the mailbox slot door. By providing theflange mailbox slot door, attack upon the lock, as by a slide hammer orthe like, does not allow the thief or perpetrator to open the mailboxslot door. The cam does not disengage from the mailbox slot door as itpasses through the side flange. If the side flange were absent, theslide hammer attack against the mailbox slot door would allow the cam todisengage from the door, allowing the door to swing open freely.

[0016] The CBU may be made of 18 gauge or other heavy stainless steel toprovide a strong barrier against physical attack and in order to protectthe mail inside.

OBJECTS OF THE INVENTION

[0017] It is an object of the present invention to provide a more securecentral box unit for central mail stations.

[0018] It is another object of the present invention to provide aninterlocking door seam that better secures double doors on central postbox stations.

[0019] It is another object of the present invention to provide aninterlocking door seam that is easily retrofittable to existing centralpost box stations.

[0020] It is yet another object of the present invention to provide aninterlocking door seam for central post box stations that accommodatesexisting internal structures such as shelving and the like.

[0021] It is another object of the present invention to secure doubledoors from being pried apart with a prybar or the like.

[0022] It is an additional object of the present invention to pry-proofdouble doors by providing an interlocking door seam that protects andshields the otherwise exposed adjoining edges of the double doors.

[0023] It is an object of the present invention to provide a more securecluster box unit (CBU) to protect mail.

[0024] These and other objects and advantages of the present inventionwill be apparent from a review of the following specification andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a perspective view of the interlocking door seam of thepresent invention with the top edge at the bottom of the figure.

[0026]FIG. 2 is a top and side perspective view of the interlocking doorseam of the present invention shown in conjunction with a central postbox station, the central post box station shown in phantom.

[0027]FIG. 3 is a side cross sectional view of the interlocking doorseam of FIG. 1 taken along line 3-3.

[0028]FIG. 4 is a side cross sectional view of the interlocking doorseam of FIG. 1 taken along line 4-4.

[0029]FIG. 5 is a rear plan view of the interlocking door seam of FIG.1.

[0030]FIG. 6 is a front plan view of the interlocking door seam of FIG.1.

[0031]FIG. 7 is a right side elevational view of the interlocking doorseam of FIG. 1.

[0032]FIG. 8 is a left side elevational view of the interlocking doorseam of FIG. 1.

[0033]FIG. 9 is a right top perspective view of the cluster box unit(CBU) of the present invention with its double doors closed.

[0034]FIG. 10 is a right front view of the CBU with the right door fullyand the left door partially open. Individual mail box slot doors arealso shown in an open position.

[0035]FIG. 11 is a cross-sectional view of the closed double doors takenfrom an area generally corresponding to Circle 11 in FIG. 9.

[0036]FIG. 12 is a partial left side perspective view of the slidinglinkage latch system as indicated by Circle 12 in FIG. 10.

[0037]FIG. 13 is a top inside perspective view of an individual mailboxslot door with a protruding cam as indicated by Circle 13 in FIG. 10.

[0038]FIG. 14 is a top side perspective view of a mailbox door slotframe, corresponding to a mailbox slot door in FIG. 13, as generallyindicated by Circle 14 in FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0039] The detailed description set forth below in connection with theappended drawings is intended as a description of presently-preferredembodiments of the invention and is not intended to represent the onlyforms in which the present invention may be constructed and/or utilized.The description sets forth the functions and the sequence of steps forconstructing and operating the invention in connection with theillustrated embodiments. However, it is to be understood that the sameor equivalent functions and sequences may be accomplished by differentembodiments that are also intended to be encompassed within the spiritand scope of the invention.

[0040] Beginning with FIG. 1, the interlocking door seam 30 of thepresent invention is shown with its concave 32 and convex 34 strips. Theinterlocking door seam 30 may be made of tempered steel or the like inorder to provide strength and constructural integrity, particularlyshould it be subject to attack by a prybar or the like. The concavestrip 32 defines the interstitial space 36 into which one of two doubledoors present in a central mail station (CMS) fits. The interstitialspace of the concave strip 32 is sufficiently wide and deep toaccommodate the edge of the first double door A including the situationwhere the edge of double door A is angled.

[0041] Additionally, the concave strip 32 may have an extending flange38 into which holes or apertures 40 may be present, allowing attachmentof the interlocking door seam 30 to the first double door A. Theextending flange 38 provides additional protection for the edge ofdouble door A while allowing greater securement of attachment of theinterlocking door seam 30 to double door A. Whereas, screws, bolts, orthe like may be used to secure the interlocking door seam 30 to thefirst double door A by attachment through the flange apertures.

[0042] The convex strip 34 curves away from the concave strip 32 thusgiving rise to the general geometrical language used herein to describethe concave nature of concave strip 32 with respect to double door A andthe convex nature of the convex strip 34 with respect to double door A.The concave strip 32 and convex strip 34 share a common edge 50 givingrise to the compact nature of the interlocking door seam 30 of thepresent invention.

[0043]FIG. 1 shows the interlocking door seam in a manner that might beconsidered upside down and backwards from the configuration shown inFIG. 2. The lower part of the interlocking door seam 30 in FIG. 1corresponds to the upper part of the interlocking door seam 30 in FIG.2. However, due to the relative proportions enjoyed between the concave32 and convex 34 strips, in order to better show the interlocking doorseam 30 of the present invention, the arrangement shown in FIG. 1 wasachieved.

[0044] As the concave 32 and convex 34 strips share the common edge 50,a compact and efficient interlocking door seam 30 is achieved thatoptimizes the material and space used to prevent prybar attack upon thedouble doors A, B of the central mail station (CMS). The convex strip 34is generally aligned with the concave strip 32 in order to accommodatethe alignment between the two double doors A, B. The interstitial space52 present between the opposite sides of the convex strip 34 is sized toaccommodate the free edge of double door B. Generally, such seconddouble doors do not have angled edges such as those that might bepresent in double door A to which the interlocking door seam 30 may beattached. Consequently, the interstitial space 52 of the convex strip 34may be correspondingly smaller in order to provide a closer fit andenhanced shielding.

[0045] Running along the free edge 60 of the convex strip 34 are anumber of spaced flanges 62. These flanges 62 provide means for guidingthe free adjoining edge of double door B into the interstitial space 52of the convex strip 34. The flanges 62 are angled outwardly from theconvex strip 34 in order to provide a greater area available to receivethe free edge of double door B. Upon contacting the flange of 62, thefree end of double door B is guided into the interstitial space 52present along the convex strip 34.

[0046] The flange of 62 may be spaced apart by gaps 70. The gaps 70 maybe present in order to accommodate shelving or other internal supportingstructures which would otherwise interfere with the closing of doubledoors A, B when the flanges 62 are pressed into the confines of thecentral mail station (CMS) by the closing of the double doors A, B. Theshelving may fit into the gaps 70 and be accommodated thereby.Additionally, vertical retention of the interlocking door seam 30 may beachieved as the shelving may interfere with the vertical travel of theflanges 62. Should the interlocking door seam move vertically, theflanges 62 will abut the adjacent shelves. This prevents stress upon thehinges of the double doors A, B and enhances their stability.

[0047] Once the interlocking door seam 30, the present invention, hasbeen attached to double door A or the like by rivets or otherwise, theinterlocking door seam 30 is ready to prevent pry bars and the like fromforcing open the double doors A, B.

[0048] Once the interlocking door seam 30 has been attached to doubledoor A, the concave strip 32 protects the free edge of double door Afrom attack by prybars or the like. When the double doors A, B areclosed, the free edge of double door B fits into the interstitial space52 of the convex strip 34. The free end of double door B is therebyprotected from prybar attack and the like, as is the seam between doubledoors A, B. The exposed curve 80 present between the two opposingportions of the concave strip 32, is generally not subject to prybarattack due to its strength, durability, and lack of an exposed edge.When a prybar is used to force its way into the interstitial space 52 ofthe convex strip 34, the prybar will encounter the second double door Band find little, if any, edge upon which to exercise its leverage. Theclose fit between double door B and the common edge 50 serve to preventprybar attack thereupon. It is difficult for a prybar to get a grip oredge there, as is true for the entire interlocking door seam 30. Infact, when prybar attack is made there, the interstitial space 52 servesto force the convex strip 34 closer to the concave strip 32 therebyenhancing the security effect of the interlocking door seam 30 of thepresent invention.

[0049] While the interstitial space 52 of the convex strip 34 is narrow,the flanges 62 serve as means by which the free edge of double door Bmay be easily fitted into the convex strip 34. Additionally, as shown inthe cross section FIGS. 3 & 4, there is an offset 72 present between thecommon edge 50 (between the concave 32 and the convex 34 strips) and theflanges 62. Thus, when the free edge of double door B is guided towardthe convex strip 34 by the flanges 62, that free edge will travel alongthe flanges 62 until it engages the common edge 50 where it is guidedinto the interstitial space 52.

[0050] As the interlocking door seam 30 of the present inventionprovides greater means by which the seam present between double doors A,B may be secured, thieves will be deterred from successfully prying openthe central mail station (CMS) and rifling the contents therein forpersonal gain. Material currently used for central mail stations (CMS)may continue to be used for such stations, however, with the fortifiedseam provided by the interlocking door seam 30, such central mailstations (CMS) are less subject to successful attack.

[0051] The interlocking door seam of the present invention may also beincorporated ab initio into a cluster box unit (CBU) in order to providea more secure mail station for the temporary holding of delivered mailuntil it can be received by the recipient.

[0052] As shown in FIGS. 9-14, the CBU 100 of present invention appearsgenerally to be a nondescript mail station for the temporary holding ofmail for its recipients. However, upon closer inspection (FIG. 10), theCBU 100 has many security features in order to defeat the interest of anmischievous thief from interfering with the proper delivery of mail.

[0053] Referring to FIG. 9, the CBU 100 is generally encased in a thickshell 102 of 18 gauge or other stainless steel that circumscribes fiveof the six sides of the generally-rectangular prism defined by the CBU.Rivets or other reinforced attachments may sturdily connect differentsections of the CBU. Furthermore, a pedestal P may provide verticalsupport, lifting the CBU 100 off of the ground for easier access.Furthermore, a shroud or extended flange 106 may circumscribe the doubledoors 108, 110 on three sides to provide protection from the elements,such as wind and rain.

[0054] Referring now to FIG. 9, the double doors 108, 110 botharticulate with respect to the main portion 112 of the CBU 100. Thereinforced, protected, or otherwise secure hinges 114 provide the pivotupon which the doors 108, 110 articulate. When closed, the doors 108,110 securely enclose the slotted or shelved confines of the main orchassis portion 112 of the CBU. By articulating upon hinges 114, thedouble doors 108, 110 provide open, free, and full access to theconfines of the chassis 112 when the double doors 108, 110 are open. Thepresent invention provides several different mechanisms by which theconfines of the CBU chassis 112 are securely confined so that the mailleft for a particular recipient is held in safekeeping until retrieval.

[0055] As set forth above, first and foremost of the means by which suchmail is secured is the use of heavy and/or reinforced materials thatwithstand physical attack without breaking. 18 gauge stainless steel orthe like is advantageously used in the present circumstances and canform the entirety of the CBU 100. Other similar or durable materials mayalso be used to good advantage.

[0056] Beyond the use of resilient strong and tamper-resident materials,the articulating elements of the CBU 100 are each individually subjectto securement and/or locking in order to provide secure, but selectable,access to the confines of the CBU 100 on an individual basis or in itsentirety.

[0057] As set forth above for the interlocking door seam 30, each of thedoors 108, 110 is circumscribed by a flange 120, 122 (respectively). Theflanges 120, 122 serve to extend the circumference of the doors 108, 110in order to eliminate edges against which a pry bar or the like might beapplied. As is well known, pry bars, such as crowbars and the like,could be used to jimmy or force open a door, particularly one with anexposed edge that lends itself to such attack. As set forth in moredetail below, the most vulnerable edges, namely those establishing theshared seam between the doors 108, 110, are generally secured in aredundant manner.

[0058] As shown in FIG. 10, and more particularly in greater detail inFIG. 12, the double doors 108, 110 are held closed by a sliding linkage130. The sliding linkage 130 is generally positioned central to the CBUin between the two double doors 108, 110. Pins 132 present on theadjacent slides of the double doors 108, 110 engage the sliding linkage130 and hooks or recesses 134 especially designed to received such pins132. The sliding linkage is slidably attached to the CBU chassis 112,but is generally held in its most downward position by gravity. Bylifting upon the lever 136 of the sliding linkage 130, the slidinglinkage 130 may be lifted along bolts passing into the sliding linkage130 through gaps or the like, in order to raise the sliding linkage 130.As the hooks or recesses 134 need only be as long as the pins 132 arewide, the displacement of sliding linkage 130 required to release thedoor pins 132 can be correspondingly small and well within the easyarticulation of the human hand.

[0059] The weight alone of the sliding linkage is sufficient to hold itdown, locking the doors 108, 110 in place. As the double doors 108, 110cannot move vertically upon their hinges, the doors 108, 110 cannot movein a way to disengage the sliding linkage 130 once they are therebyengaged. The doors 108, 110 only move horizontally, a direction which isagainst the vertically-articulating sliding linkage 130 when the doors108, 110 are locked by the sliding linkage 130.

[0060] In order to provide securement for the door pins 132, the hooksor recesses 134 should be sufficiently reinforced in order to provide astrong barrier to the travel of the door pins 132 and the attached doors108, 110 should the pins be brought into contact with the hooks 134.Such a circumstance could arise from a pry bar attack on the doubledoors 108, 110. As for the entirety of the CBU 100, 18 gauge stainlesssteel or other similarly durable and resilient materials may be used toconstruct the sliding linkage 130. As shown in FIG. 10, a special postperson mail slot door 138 may be used to access the lift lever 136 tothereby provide access to the entire interior confines of the CBU 100.The post person's mail slot box door 138 may itself have a insertionslot 140 into which letters, cards, and sufficiently small parcels maybe inserted for pickup by the post person.

[0061] As is known in the art with respect to prior mailbox units,parcels may be delivered to individuals by means of the larger mailboxslots 150, 152. Keys fitting the doors that individually secure theseparcel slots 150, 152 may be left in the mailbox slot for the personreceiving the parcel. Parcels for a single individual can be left ineither or both of the parcel boxes 150, 152 with the keys for theirdoors left in the person's mailbox slot by the post person. In thismanner, persons may retrieve parcels from the CBU 100 without having totravel to the local post office in order to pick them up. Uponretrieving their parcels from the parcel slots 150, 152, the recipientmay return the keys to the post person by inserting them through theinsertion slot 140. As the receipt of parcels may only be made on anintermittent basis, such keys may actually be stored in the parcel slots150, 152 themselves until needed.

[0062] As for the first interlocking door seam 30, above, the opposingflanges 160, 162 of the double doors 108, 110, respectively, participatein coordinated tandem in order to provide a more protected and lessvulnerable shared seam which might be subject to attack by a thief. Asindicated in FIGS. 9 and 11, the double doors 108, 110 may beconstructed so that one double door, in this case the right double door108, is dedicated as an interior double door that when closed is alwaysinterior to the outer double door, in this case door 110.

[0063] As shown in FIG. 11, the protruding flange 160 of the innerdouble door 108 fits into a receiving shroud 164 that receives andprotects the exposed flange 160. The receiving shroud 164 could be addedon into the interior of the outer double door 110 during constructionadjacent its extending flange 162. Alternatively, a shroud 164 may beformed integrally with the door 110 in order to provide the smallestpossible gap or separation 170 between the inner double door 108 withits flange 160 and the outer double door with its flange 162. Forexample, such a shroud 164 could be achieved without the use of theouter side of the shroud 174, trapping the inner door flange 160 betweenthe inner side 172 of the shroud 164 and the outer door flange 162. Whenthe receiving shroud 164 is added separately to the outer door 110, theoutermost portion adjacent flange 162 may be extended farther in orderto provide a significantly smaller space, if any, that might be used toinsert the leading edge of a pry bar.

[0064] As shown in FIG. 11, the would-be thief has to work againstseveral individual layers of strong metal or the like, in order todefeat the securement of the flange 160 of the inner door 108 in orderto obtain access to the confines of the CBU 100.

[0065] For example, in order to defeat the receiving shroud 164 and itsprotection of the inner door flange 160, the thief has to engage inseveral arduous tasks. First, the thief must peel back the entirety ofthe external extending flange 162 to completely expose the innerinternal flange 160. Initially, a thief might think by prying upon theseam 170 between the two doors, that the outer door 110 will be poppedor otherwise liberated from its locking mechanism in order to allow thatdoor to swing free. Instead, the thief must peel back the outerextending flange 162 to completely expose the inner protruding flange160. In so doing, the thief must work against the inner extending flange160 which itself presses against the inner portion of 172 of thereceiving shroud 164. As the receiving shroud 164 is attached to theouter door 110, the thief is actually working the outer door 110 againstitself. In prying back the outer extending flange 162, the thief isactually holding the outer door 110 in place via the inner edge of 172the receiving shroud 164.

[0066] As the receiving shroud 164 generally extends the entire lengthof the extending flange 162, the thief must work all along the entirelength of the outer door extending flange 162. As the thief is generallyworking against the 18 gauge stainless steel or other similar material,this takes some time. During such time, the thief subjects himself todetection and arrest for tampering with mail, a federal felony.

[0067] If the thief should persist in the peeling back of the outer doorextending flange 162, he or she will then encounter the inner doorextending flange 160 which then must also be peeled back from the innerside 172 of the receiving shroud 164. As the thief must then work in thetighter confines of the remnants of the peeled back outer door extendingflange 162, the pry bar may be limited in its working room in order toengage any gap or seam between the inner door extending flange 160 andthe receiving shroud 164.

[0068] However, should the diligent thief pursue his or her efforts,upon subjecting him or herself to the second arduous task of peelingback the inner door extending flange 160, the thief now encounters theinner side 172 of the receiving shroud 164. This third layer must alsobe peeled away in order to obtain access to the sliding linkage 130and/or the door pins 132 which must be disengaged from one another inorder to allow the doors 108, 110 to swing upon their hinges and allowaccess to the confines of the CBU 100.

[0069] As can be seen by the foregoing, thieves who are looking forquick and easy access to the CBU 100 are generally defeated by thedifficulty encountered in forcing open the double doors 108, 110 at thecommon seam 170. Other doors known in the art subject to such attack andare generally easily opened if they do not have such mechanical measurestaken to prevent such unauthorized access.

[0070] If a thief should, instead of attacking the entirety of thedouble doors, instead attack one of the individual mailbox slot doors180 (FIGS. 10, 13 and 14), that thief will find that similar measureshave been taken to ensure that such unauthorized excess is not easilyachieved.

[0071] In order to provide full and complete access to the interior ofthe CBU 100, each of the double doors 108, 110 swing fully away from thecentral CBU chassis 112 area opening up the individual mail slots 182for insertion of delivered mail. Each of the doors 108, 110 provide aframe in which a number of individual mailbox slot doors 180 articulateupon reinforced or otherwise protected hinges. As shown in FIGS. 13 and14, each of the individual mailbox slot doors 180 has a lock 184 whichmay be pivoted by insertion of the proper key 186 in order to pivot alocking cam 188. The mailbox slot door 180 is not a flat plate, butinstead is flanged on all three sides, those sides not connected to themailbox slot door hinge. The side flange 190 has a slot or gap 192through which the cam 188 articulates. If for some reason, the lock 184should fail, the mailbox slot door 180 will not necessarily open as thecam 188 will not be displaced (by the lock failure) from its position(in a locked state) of travel through the side flange gap 192.

[0072] Turning now to FIG. 14, the right double door 108 provides anumber of mailbox slot door frames 200 over which the mailbox slot doors180 fit. Shrouds 202, much like the double door receiving shroud 164,receive the leading edges of the mailbox slot door flanges, includingthe side flange 190, in order to protect them from attack. Additionally,the mailbox slot door frame 200 has a cam slot 204 corresponding to theside flange slot 192 in the mailbox slot 180. In order to close themailbox slot door 180, the key 186 must be turned in the lock 184 inorder to pivot the cam 188 away from the side flange slot 192. Theindividual mailbox slot door 180 then closes with the flanges, with theframe flange receiving shrouds 202 receiving the mailbox slot doorflanges, including the side flange 190. When the mailbox slot door 180is completely closed, the side flange slot 192 is directly opposite andaligned with the frame cam slot 204. The key 186 may then be turned theopposite direction in lock 184 in order to bring the locking cam 188 totravel through both the side flange slot 192 and then frame cam slot204, thereby locking the mailbox slot door 180 into the double door 108.Upon removal of the key 186, the mailbox slot door 180 has been lockedinto place and cannot be opened until the key is inserted and turned inthe lock 184.

[0073] The unlocking and opening of the individual mailbox slot door 180allows a person to pick up their own mail without providing access tothe other mailbox slots. The mailbox slot door key 186 for oneindividual mailbox slot door does not fit any of the other mailbox slotdoors.

[0074] In order to obtain unauthorized access to the mailbox slot 182 bydefeating the lock mechanism 184, as by using a pry bar, the would-bethief encounters several difficulties.

[0075] Should the thief attempt to defeat the lock mechanism 184 with aslide hammer or the like, the thief will first turn the slide hammermechanism into the key slot (not shown) of lock 184. Upon so engagingthe lock, the thief will then engage the slide hammer by slamming thesliding weight against the far end to attempt to defeat the lock 184. Ifthe thief should succeed in the attempt, the thief will find that theside flange 190 with its flange slot 192 preserves the secure nature ofthe mailbox slot 182. Although the lock may be defeated 184, the lock'sdefeat does not remove the cam 188 from its position as inserted throughboth the side flange 190 through the side flange slot 192 and into themailbox slot door frame 200 through the cam slot 204.

[0076] Although the owner or user of the mailbox slot 182 will no longerbe able to access his or her mail via the mailbox slot door 180, themailbox slot door 180 will not open as the side flange 190 engages thecam, preventing the mailbox slot door 180 from opening.

[0077] If the side flange 190 were not present, defeating the lock 184would generally allow easier access to the mailbox slot 182 as the cam188 could generally be pried away from the door frame 200 at frame camslot 204. Such a defeat of the cam 188 becomes a more difficult endeavorwith the presence of the side flange 190 with its side flange cam slot192.

[0078] If, in addition to or alternatively, the thief attempts to prythe mailbox slot door 180 open, the thief encounters the samedifficulties described above in conjunction with FIGS. 9 and 11regarding the receiving shroud 164 and its engagement of the inner doorextending flange 160.

[0079] When the thief tries to pry open the mailbox slot door 180, thethief does so by inserting the pry bar between the mailbox slot doorframe 200 and one of the extending flanges present along the mailboxslot door 180, such as side flange 190, (FIG. 13). As the thief attemptsto pry the door open, the flanges are secured by the receiving shrouds202. The receiving shrouds 202 reinforce the side flanges (referred togenerally herein by reference number 210). The reinforcement of the sideflanges 210 by the receiving shrouds 202 effectively doubles, or eventriples, the thickness of the side flanges 210. Because there is someseparation, difference, and distinction between the side flanges 210 andtheir respective receiving shrouds 202, the strength available from theflange-shroud combination generally exceeds that of a piece of metal ofthe same thickness much in the same way that a cable provides greaterstrength than a single strand of metal of the same thickness.

[0080] A thief interested in an easy target will readily find that theCBU 100 of the present invention provides one of the least desirabletargets with respect to mail theft. Consequently, it is of someadvantage to provide a degree of high visibility to the CBU's of thepresent invention so that they may be easily recognized and easilyavoided by thieves.

[0081] By providing shrouded flanges for intersecting door seams on boththe double doors 108, 110 and the individual mailbox slot doors 180, theCBU 100 of the present invention provides enhanced barrier meanspreventing forced entry into the CBU. Additionally, the use of thesliding linkage 130 provides a greater degree of security as theextending door pins 132 are easily disengaged from the sliding linkage130 by a post person with authorized access yet provide a significantand very difficult barrier to a thief.

[0082] While the present invention has been described with regards toparticular embodiments, it is recognized that additional variations ofthe present invention may be devised without departing from theinventive concept.

[0083] While the present invention has been described with regards toparticular embodiments, it is recognized that additional variations ofthe present invention may be devised without departing from theinventive concept.

What is claimed is:
 1. An interlocking door seam for preventing doubledoors having adjoining edges from being pried apart, comprising: a firstconcave strip conforming to a first adjoining edge of a first door ofsaid double doors, said first concave strip attachable to said firstadjoining edge, said first concave strip generally extending along theentirety of said first adjoining edge to shield said first adjoiningedge from prybars and the like; and a second convex strip connected toand generally aligned with said first concave strip, said second convexstrip able to releasably receive a second adjoining edge of a seconddoor of said double doors, said second convex strip generally extendingalong the entirety of said second adjoining edge to shield said secondadjoining edge from prybars and the like; whereby a seam present betweentwo double doors may be protected from attack by prybars and the like byattaching said first concave strip to said first door and fitting saidsecond door into said second convex strip when said first and seconddoors are closed.
 2. The interlocking door seam of claim 1 , furthercomprising: said first concave and said second convex stripsaccommodating an overlap of the double doors to prevent exposure of apryable seam between overlapping double doors.
 3. The interlocking doorseam of claim 1 , further comprising: said first concave strip having arelatively wide interstitial space to accommodate an angled edge of saidfirst adjoining edge of said first door.
 4. The interlocking door seamof claim 1 , wherein said second convex strip further comprises: angledflanges, said angled flanges angled away from said second convex stripand said first concave strip, said angled flanges facilitating receptionof said second adjoining door edge by said second convex strip.
 5. Theinterlocking door seam of claim 4 , wherein said angled flanges furthercomprise: angled flanges defining gaps between said angled flanges, saidgaps able to receive and accommodate protruding shelves.
 6. Theinterlocking door seam of claim 1 , further comprising: said firstconcave and second convex strips sharing a common side.
 7. Theinterlocking door seam of claim 1 , wherein said first concave stripfurther comprises: an extending flange, said extending flange providinggreater connective surface for attachment of said first concave strip tosaid first adjoining door edge.
 8. The interlocking door seam of claim 1, wherein the interlocking door seam complies with postal regulationsand accommodates double doors used for central postbox stations.
 9. Theinterlocking door seam of claim 1 , further comprising: said firstconcave and second convex strips forming a cross section generallysimilar to an “S” or “Z” shape.
 10. An interlocking door seam forpreventing double doors having adjoining edges from being pried apart,the interlocking door seam complying with postal regulations andaccommodating double doors used for central postbox stations,comprising: a first concave strip conforming to a first adjoining edgeof a first door of said double doors, said first concave stripattachable to said first adjoining edge, said first concave stripgenerally extending along the entirety of said first adjoining edge toshield said first adjoining edge from prybars and the like, said firstconcave strip having a relatively wide interstitial space to accommodatean angled edge of said first adjoining edge of said first door, saidfirst concave strip having an extending flange, said extending flangeproviding greater connective surface for attachment of said firstconcave strip to said first adjoining door edge; and a second convexstrip connected to and generally aligned with said first concave strip,said second convex strip able to releasably receive a second adjoiningedge of a second door of said double doors, said second convex stripgenerally extending along the entirety of said second adjoining edge toshield said second adjoining edge from prybars and the like, said secondconvex strip having angled flanges angled away from said second convexstrip and said first concave strip, said angled flanges facilitatingreception of said second adjoining door edge by said second convexstrip, said angled flanges defining gaps between said angled flanges,said gaps able to receive and accommodate protruding shelves or thelike; said first concave and second convex strips sharing a common sideand accommodating an overlap of the double doors to prevent exposure ofa pryable seam between overlapping double doors, said first concave andsecond convex strips forming a cross section generally similar to an “S”or “Z” shape; whereby a seam present between two double doors may beprotected from attack by prybars and the like by attaching said firstconcave strip to said first door and fitting said second door into saidsecond convex strip when said first and second doors are closed.
 11. Acentral mail box station for providing a plurality of mail delivery postboxes, comprising: an external body having an interior and protectingsaid interior from ambient weather including wind and rain; first andsecond oppositely opposed double doors opening outwardly from a sharedcentral area coupled to said external body; a first concave stripconforming to a first adjoining edge said first, said first concavestrip connected to said first adjoining edge, said first concave stripgenerally extending along the entirety of said first adjoining edge toshield said first adjoining edge from prybars and the like; and a secondconvex strip connected to and generally aligned with said first concavestrip, said second convex strip able to releasably receive said seconddoor, said second convex strip generally extending along the entirety ofsaid second adjoining edge to shield said second adjoining edge fromprybars and the like; whereby a seam present between said first andsecond doors may be protected from attack by prybars and the like byattachment of said first concave strip to said first door and fittingsaid second door into said second convex strip when said first andsecond doors are closed.
 12. The central mail box station of claim 11 ,wherein said interlocking door seam further comprises: said firstconcave and said second convex strips accommodating an overlap of saidfirst and second double doors to prevent exposure of a pryable seambetween said overlapping double doors.
 13. The central mail box stationof claim 11 , wherein said interlocking door seam further comprises:said first concave strip having a relatively wide interstitial space toaccommodate an angled edge of said first adjoining edge of said firstdouble door.
 14. The central mail box station of claim 11 , wherein saidinterlocking door seam further comprises: angled flanges, said angledflanges angled away from said second convex strip and said first concavestrip, said angled flanges facilitating reception of said secondadjoining door edge by said second convex strip.
 15. The central mailbox station of claim 11 , wherein said angled flanges further comprise:angled flanges defining gaps between said angled flanges, said gaps ableto receive and accommodate protruding shelves present in said interiorof said central mail box station.
 16. The central mail box station ofclaim 11 , wherein said interlocking door seam further comprises: saidfirst concave and second convex strips sharing a common side.
 17. Thecentral mail box station of claim 11 , wherein said first concave stripfurther comprises: an extending flange, said extending flange providinggreater connective surface for attachment of said first concave strip tosaid first adjoining door edge.
 18. The central mail box station ofclaim 11 , wherein said interlocking door seam complies with postalregulations and accommodates double doors used for central postboxstations.
 19. The central mail box station of claim 11 , wherein saidinterlocking door seam further comprises: said first concave and secondconvex strips forming a cross section generally similar to an “S” or “Z”shape.
 20. A central mail box station for providing a plurality of maildelivery post boxes, comprising: an external body having an interior andprotecting at least one postbox present in said interior from ambientweather including wind and rain; first and second oppositely opposeddouble doors opening outwardly from a shared central area, said firstand second double doors coupled to said external body; a first concavestrip conforming to a first adjoining edge of said first double door,said first concave strip attached to said first adjoining edge, saidfirst concave strip generally extending along the entirety of said firstadjoining edge to shield said first adjoining edge from prybars and thelike, said first concave strip having a relatively wide interstitialspace to accommodate an angled edge of said first adjoining edge of saidfirst double door, said first concave strip having an extending flange,said extending flange providing greater connective surface forattachment of said first concave strip to said first adjoining dooredge; and a second convex strip connected to and generally aligned withsaid first concave strip, said second convex strip able to releasablyreceive a second adjoining edge of said second double door, said secondconvex strip generally extending along the entirety of said secondadjoining edge to shield said second adjoining edge from prybars and thelike, said second convex strip having angled flanges angled away fromsaid second convex strip and said first concave strip, said angledflanges facilitating reception of said second adjoining door edge bysaid second convex strip, said angled flanges defining gaps between saidangled flanges, said gaps able to receive and accommodate protrudingshelves or the like; said first concave and second convex strips sharinga common side and accommodating an overlap of the first and seconddouble doors to prevent exposure of a pryable seam between saidoverlapping double doors, said first concave and second convex stripsforming a cross section generally similar to an “S” or “Z” shape;whereby a seam present between said first and second double doors may beprotected from attack by prybars and the like by attachment of saidfirst concave strip to said first door and fitting said second door intosaid second convex strip when said first and second double doors areclosed.